Experiments subjecting bed bugs to atmospheres of carbon dioxide resulted in 100 % mortality of all stages within 6 hours in an atmosphere of 100% C02, while a 60% volume produced the same effect within 24 hours. An atmosphere of 98% nitrogen resulted in only 10 - 20 % mortality after 72 hours.<ref>[http://www.icup.org.uk/reports/ICUP511.pdf ''Efficacy of controlled atmospheres on cimex lectularius.'' Proceedings of the 3rd International Conference on Urban Pests]</ref>

Experiments subjecting bed bugs to atmospheres of carbon dioxide resulted in 100 % mortality of all stages within 6 hours in an atmosphere of 100% C02, while a 60% volume produced the same effect within 24 hours. An atmosphere of 98% nitrogen resulted in only 10 - 20 % mortality after 72 hours.<ref>[http://www.icup.org.uk/reports/ICUP511.pdf ''Efficacy of controlled atmospheres on cimex lectularius.'' Proceedings of the 3rd International Conference on Urban Pests]</ref>

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====Chlorine dioxide====

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In clinical tests chlorine dioxide has been shown to be effective in killing bedbugs. <ref>[http://www.ncbi.nlm.nih.gov/pubmed/22476276 Gibbs SG, Lowe JJ, Smith PW, Hewlett AL., March 2012, ''Gaseous chlorine dioxide as an alternative for bedbug control,''] Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center College of Public Health</ref>

A Bed bug is any of approximately 75 species of a small parasitical insect of the family Cimicidae, particularly the common bed bug (Cimex lectularius) of the temperate areas of the northern hemisphere. Bed bugs are an ectoparasite, characterized by the nocturnal feeding of blood from man or warm-blooded animals.

Description

Bed bugs are approximately a fifth to a quarter of an inch (4-5 millimeters) long. They are broad and flat in shape, brown in color, and glisten from a distinctive, smelly oil secreted from scent glands. The wings are scale-like and vestigial. Females lay about 200 or more eggs during reproductive periods, and can lay around a thousand during several such periods within a year.

Bed bugs feed chiefly at night;[1] in the wild they feed on the blood of birds and small mammals, and within human-inhabited areas they feed upon domesticated animals as well as man. They retreat to their hiding places during the daytime, using up to several days in which to digest their food.[2] Most bed bugs live full time within eight feet of where humans sleep. When hiding they are generally found in bedding and mattresses (hence the name), nearby furniture, carpeting, within dressers and clothes, curtains, and cushions.

History

Bed bugs have been plaguing humans since ancient times. Aristophanes wrote “The Clouds” in 423 B.C. referring to bed bugs living in a couch. Eva Panagiotakopulu, a University of Sheffield archaeologist, found that bed bugs have lived with man for at least 3500 years. [3]

Bed bugs spread throughout Europe and Asia, reaching Italy by 100 A.D., China by 600 A.D., and Germany and France in the 1200s and 1400s, and are mentioned in medieval European texts and in classical Greek writings back to the time of Aristotle. The earliest record of bed bugs in England is that of 1583. Migrating with European explorers to America, infestations first arose in busy seaport towns, and later on appearing farther inland. This pattern that was repeated in the late 1990s, with the reports of infestations first coming from such gateway cities as New York, Los Angeles, San Francisco and Miami. [4] A 1920s guide advises treating infested mattresses with "high-test gasoline" and a 1935 guide prescribed powdered calcium cyanide.

In the 1800's, bed bugs were significant pest in parts of both the United States and the United Kingdom. Government Entomologist Dr. Riley, PhD, described the ubiquity of bed bugs in 1889:

“

I have occasionally met with a favored individual who had never seen a bed bug; but such fortunate people are rare and there are very few housekeepers who have not, by accident perhaps, or through slovenly servants, made the intimate acquaintance of the ubiquitous pest…. It’s odor and the effects of its bites are universally known, and the word “bed buggy” has entered our literature as descriptive of a particular class of odors.[5]

”

In the 1930s there were large sections of London where every house was infested, resulting in an investigation by the Ministry of Health and the Public Health Act of 1936 which required councils to take action. Toxic fumigation using sulfur dioxide (sulfur candles) or hydrogen cyanide, are reported to have helped reduce infestations by up to 80% in one town under study. Before World War Two the primary treatment was either heat or fumigation, and barriers behind walls were even constructed to prevent bed bugs from crawling up, while harborage was encouraged using wire mesh below, which periodically would be burned with a blow torch. Some state laws once required that the furniture be tagged as fumigated before it could be resold. DDT became the primary insecticide beginning in 1945, and declining numbers overall continued from the late 30s through 1980s until the recent resurgence.

Diligence and use of the pesticide DDT in the 1950s and broad-based pesticides also resulted in a dramatic reduction of bed bugs overall in the United States, though significant reservoirs of bed bug infestation persisted
through this period, particularly in inner-city areas. During the bed bug recession period of the 1950s, infestations were
mainly found in homeless shelters, and prisons, while during in the period 1967-73, about 61% of infestations were found in domestic residential property, while about 25% were in institutional settings.[6][7][8]

A current resurgence of bed bug infestations appears to have started almost synchronously in the late 1990’s in Europe, the United States, and in Australia. 2007 data from a survey of pest control companies in the latter country indicated a 4500% increase over a seven year period.[9][10]

According to a new survey from the National Pest Management Association (NPMA), one out of five Americans has had a bed bug infestation in their home or knows someone who has encountered bed bugs at home or a hotel.[11] The University of Kentucky, which has provided much research on bed bugs, and the United States' National Pest Management Association reported that 95% of 521 U.S. pest management companies reported encountering a bed bug infestation in the past year. [12][13] Canada reported similar numbers (98%), as well as Europe (92%), and Africa/Middle East (90%). In contrast, prior to the year 2000 only 25% of U.S. survey respondents reported bed bug infestations. In addition, 76 percent of survey respondents affirmed that bed bugs are the most difficult pest to treat, more so than cockroaches, ants and termites. "The results of the global study suggest that we are on the threshold of a bed bug pandemic, not just in the United States, but around the world," said Missy Henriksen, vice president of public affairs for NPMA. The global survey included pest control firms in Latin America and Asia, where stronger, organophosphate chemicals are permitted.[14][15] In the United States, state and local government officials say they are being overwhelmed with complaints of bed bug infestations.

Causes of resurgence

The prime causes of the increased bed bug infestations are yet debated. Social aspects such as increased travel immigration and population density, clutter, etc. and even climate change (dismissed) have all been blamed, as well as changing pest control products and methods and the development of strains of bed bugs that are resistant to insecticides.

As regards the latter, this theory for the cause of bed bug resurgence postulates that use of DDT and its successors (DDT was banned, effective Jan 1, 1973) on household pests such as the German cockroach also killed bed bugs before they became established in a home. After roaches developed resistance to insecticides being used, hydramethylnon bait was introduced in the early 1980s, which provided superior effectiveness. This resulted in a switch from spraying and dusting and baseboard treatment which also controlled bed bug populations, to the use of baits and Insect Growth Regulators (IGRs) in the early 1990s. In addition, many more broad spectrum residual pesticides besides DDT were banned or heavily restricted in the United States and many developing countries during the past few decades, due to the danger of harmful effects to humans. These included the organophosphates, chlorpyrifos (Dursban, and to which bed bugs show no resistance to) and diazinon, and the carbamate propoxur (Baygon, also deadly) which had became the indoor insecticides of choice to control cockroaches and most other pests. Replacing them were pyrethroid insecticides, all of which bed bugs have now developed resistance to.[16][17]

Dr. Michael Potter, a professor and urban entomologist at the University of Kentucky, stated, “What made this problem pretty much go away for decades was the availability of very effective, long-lasting insecticides that were cheap, affordable and available not only to pest control companies but to consumers over the counter,” he said. Having conducted a study comparing older pesticides to those used today, he found that insecticides in two families, organophosphites and carbamates, are especially effective at eradicating bed bugs. While some of these compounds can be found in insect traps or spot treatments, most are no longer permitted for use by pest-control professionals in North America.[18]

In the light of colonies from all over the United States having a very high resistance to pyrethroid-type pesticides, some believe that these bugs likely came from a region where those pesticides are used extensively around beds. Entomologist Coby Schal believes that it is likely the bed bugs found in U.S. hotels, homes and apartments may be the progeny of bugs which came from areas of the world such as Africa, Southeast Asia or South America, in which bugs might have often encountered pyrethroid-treated bed nets, designed to prevent biting by malaria-carrying mosquitoes, and thus developed resistance to this class of insecticides.

An additional problem as a result of to minimal problems with bed bugs overall in the United States, was that research initiatives on bed bugs ceased in the 1950s.[19]

With many factors possibly contributing to the exponential rise in bed bug infestations, it is difficult to know what physically is the primary caused of the current bed bug epidemic. Potter also, stated, "The bottom line is it may be a convergence of all those factors, but none of that really explains the rapid increase in recent years," said
[20]

Life and behavior

Reproduction, development and longetivity

Like stable flies, sucking lice, bed bugs, mosquitoes, true bugs, and aphids, bed bugs have a piercing-sucking mouthpart consists of a long slender tube which is forced into plant or animal tissue to suck out fluids or blood.[21] Like mosquitoes and certain other insects, bed bugs inject an anticoagulant into their host before extracting blood, which results in a burning itching in persons who allergically react to the anticoagulant.

Male bed bugs grab and attempt to mate with any other bed bug that has had a full meal of blood recently, using its hypodermic reproductive appendage. Females grow a mass of the kinds of cells associated with immune defense in the the abdominal area most commonly pierced by the male. Male bed bugs lack this, and when homosexual mating attempts are made upon a male then the victim releases a blend of chemicals known as the bed bug alarm pheromone. This recent discovery has resulted in some bed bug insecticides containing the pheromone. [22] Bed bugs also release this substance when they are frightened, the smell of which has been described as a sickening sweet odor or as rotting raspberries.[23] Bed bugs in an all-male confinement experiment had reduced longevity compared to singly held males.[24]

Males will mate with females much more often (roughly 20 times more) than necessary for fertilization of eggs and as a result the females live about 25% less long than they would otherwise.[25]

An impregnated female bed bug will produce between 1- 7 eggs per day (but up to 20) for about 10 days after a single blood meal, and will then have to feed again to produce more eggs. The female bed bug lays her eggs in cracks and crevices in the vicinity of the host (and she seem to prefer wood over metal and plastic) and cements them firmly in position. The eggs are sticky, and able to adhere to most anything, and are yellowish-white, approximately 1 millimeter (1/25 inch) in length (a little larger than a speck of dust) and are covered with a protective layer, so that immersion in water does not kill them as would adult bed bugs. The estimated total number of eggs which may be laid by one female is estimated to be from about 113 to as high as 345. Under optimal conditions (between 70° F and 90° F), and with regular feeding, a bed bug population can double every 16 days. At room temperature (average 70° F), 60 percent of the eggs will hatch when they are 6 days old; around 90 percent will have hatched by the time they are 9 days old. Once born, the bed bug will go through five growth (molting) stages (shedding the exoskeleton) as nymphs---- each nymphal stage requiring a blood meal and each time shedding its skin ---- before it becomes an adult, and able to reproduce. After hatching the color of the bed bug is like that of straw and no bigger than a pinhead, and which begin to feed immediately.

A second stage nymph is about the size of apple seed, and as it fills itself with blood then its color goes from white to bright red. Nymphal stages last from about 4 days to 24 days based on temperature and other environmental conditions. In ideal temperatures (about 70-90°F), the bugs go from birth to adulthood in a month to six weeks. Studies show that under favorable conditions more than 80 percent of all eggs survive to become reproductive adults. Adults are approximately 3/16-inch long and reddish-brown, with oval, flattened bodies.[26][27]>

Cooler temperatures and less blood meals will slow bed bug development down, and at 55 degrees bed bug development and egg production stops,[28] but much lower temperatures are required to kill them, as adult laboratory bed bugs can survive without feeding for over a year in temperatures around 50°F, and the nymphs can survive for 3 months. In the laboratory at 10% humidity and 44°F degrees, bed bugs have survived as long as 560 days without a blood meal.[29]

The original source of longevity statistics appears to be from a study from A.W Bacot in 1914, in which he reported that "After a single meal one newly hatched bug out of three lived for 270 days; while, out of 30 immature bugs in various stages of development, 7 were living and able to feed after a fast of 18 months."[30] However, while this
may have been true for individual bed bugs in the UK living at very low temperatures, research showed that on average, modern bed bugs (at any life stage) collected from homes in the United States and held at room temperature without feeding, would die within 70 days. It is thought that these bed bugs were dying of dehydration, rather than starving to death. Also, the most recent studies indicate that a well-fed adult bed bug held at room temperature (avg. 70° F), will live between 99 and 300 days in the laboratory.[31][32][33]

Feeding, nesting and travel

Adults may feed many times throughout their lifespan, every 3-7 days varying with temperature and other factors.[34] When bed bugs bite, like mosquitoes, they inject an anesthetic that prevents the host from feeling the bite, and an anticoagulant for blood flow. Bed bugs are normatively nocturnal, and though they can bite during the day or with light, they usually occur while people are sleeping, usually when the host is in their deepest part of sleep, most typically 3-5AM. Feeding takes three to 15 minutes, depending on maturity, and immediately after feeding the bug crawls off to digest their meal in a safe place. The bite sites are usually small, pinprick-sized lesions that may or may not become inflamed, though often the human host finds that they itch. Bite marks can be random or in a straight line.[35][36] The human bedbug has glands on its body which secrete an odorous oily material, leaving a room that is heavily infested with a characteristic odor. After feeding the bed bug defecates, which material appears as small black specks on mattresses, sheets or in the vicinity of their hiding places.[37]

Bed bugs do not have nests like ants or bees, but do tend to congregate in habitual hiding places. They are attracted by the carbon dioxide and (secondarily) the heat that people generate, and they will feed only through a membrane.[38] Bed bugs can travel at the rate of 3 feet per minute and 100 feet in one night, but they tend to live within 8 feet of where people sleep. They appear to have an affinity for wood and fabric more so than metal or plastic. Bed bugs hide in such places as mattresses seams, box springs, bed frames and headboards, dresser tables, cracks or crevices, baseboards, behind wallpaper, and under any clothes, clutter or objects around a bed. Their small flat bodies allow them to fit into the smallest of spaces and they can remain in place for long periods of time, even without a blood meal. Bed bugs can be transported from place to place by people as they travel, and eggs and instar nymphs are especially hard to detect.

In addition to bites, bed bugs are made evident by areas marked by dark spotting and staining, which is the dried blood excrement of the bugs. Dark spots of dried bed bug excrement are often present along mattress seams or wherever the bugs have resided. Also present are eggs and eggshells, the brownish molted skins of maturing nymphs and the bugs themselves, though these may be hidden more deeply. Less often one may see rusty or reddish blood smears on bed sheets or mattresses from crushing an engorged bed bug. Some companies are beginning to use canines for detecting infestations, which, if properly trained, can be very effective.[39]

Although bed bugs have the ability to drink water through their proboscis, they appear to do so rather sparingly, as they rely on blood to replenish water stores; none of the bed bugs examined in any stage had the capacity to absorb water vapor. As the bed bugs mature they need less water.[40]

Bed bugs can run at a rate of 1 inch per second/4ft. per minute, and can climb most walls and cling to ceilings, but are thought to be unable to detect a human presence beyond 5 feet.[41] As bed bugs become active when sensing human presence, in the 1960s the US Army considered them for use in a portable insect ambush detector or a stationary intrusion detector device.[42]

Effects of climate on longevity

Bed bugs are remarkably resistant in almost every sense of the word, and are comfortable within all but the extremes of most inhabitable climates. They have a wide humidity tolerance range but tolerate dry climates better than humid. They can adapt to a wide range of temperatures, and remain active in a temperature as low as 44°F, as long as they are held at an intermediate temperature for a few hours first. Bed bugs have evidenced that can survive freezing temperatures (32°F) for days and tolerate much lower temperatures (5°F) for short periods.[43][44] Bed bugs of all stages of maturity can survive at least 5 days at 14°F, but all stages die after exposure to -26°F for 15 minutes. The upper lethal temperature for nymphs and adults is 113°F and 115°F for eggs.[45]

Health issues

Bed bugs have been found to be infected with over 25 disease organisms such as plague, relapsing fever, tularemia and Q fever,[46] but are not known to transmit disease to humans, despite possible associations with hepatitis B and Chagas disease. However, their bites often do leave red itchy welts on human skin due to an allergic reaction.[47]

An addition issue is the stress caused by bed bugs. Respondents of one survey reported that 99% of clients who have had bed bugs were “upset and concerned” while 76 percent of surveyed respondents also reported that bed bugs are the most difficult pest to treat, more so than cockroaches, ants and termites.[48]

Control and eradication

Eradication of bed bugs often necessitates integrated pest management (IPM), which includes

Vacuuming the mattress, especially tucks and along seams. Kill any live bugs using a spray of 70 or higher percent isopropyl alcohol.

Isolating the bed from walls and coating the bed legs for 3 to 5 inches with petroleum jelly, and or encasing the bed legs in a water filled container to stop bed bugs (who can jump, but not swim) from crawling up into the bed is typically recommended. Box spring encasements are also promoted.

Sealing cracks and crevices which bed bugs can hide and lay eggs (which can be as small as the width of a credit card) around the area in which bits occur.

Washing bedding and clothes in 140°F degree water and drying at high heat, especially the latter which can be used alone.

Dusting with pesticides such as silica or diatomaceous earth.

Judicious use of effective chemical pesticides, beginning with non-repellent types (such as Phantom, where legal).

Chemical insecticides

ChemicalInsecticides known to control and kill bed bugs fall into four main different categories, with first being organochlorines, which include DDT. being powerful but also the most notorious class of pesticides is aldrin, chlordane, endrin, endosulfan, dicofol and others. These are typically effective against a broad spectrum of insects, and are relatively low in toxicity to mammals, but they often remain in the environment long after application (especially DDT) and in organisms long after exposure, which led to most of them of them being banned or their use being very restricted.

The second class is the organophosphates (OPs), which include parathion, malathion, diazinon, dichlorvos, chlorpyrifos, pirimiphos methyl (Actellic). These work by effecting over-stimulation of the nervous system which eventually causes the insect to die. While these break down much faster than organochlorines, they have much greater acute toxicity and can effects mammals as well as insects. After the passing of of the Food Quality Protection Act, a 10-year review by the Environmental Protection Agency (EPA)resulted in 17 of of the 49 of the OP pesticides which had been registered for use in pest control being banned or heavily restricted, including the popular household pesticides diazinon and chlorpyrifos.

The third class is that of carbamates, which include carbofuran, aldicarb (Temik), chlorfenapyr (Propoxur), carbaryl (Sevin), and bendiocarb (Ficam). Carbamates typically degrade faster than organochlorines, and some of them can be just as lethal, while others are seen as less toxic. The use of such is restricted by the EPA, and which has banned the highly toxic carbofuran, while the manufacturer of bendiocarb has voluntarily cancelled its registration, which can cost up to $100 million in order to obtain EPA approval.

Regarding the above classes being registered and intended for bedbug control (among other insects), on researcher (2007) found no organochlolines, and out of 341 organophosphates products, most had been cancelled, and only 24 products were available, with the active ingredient being either malathion or DDVP (dichlorvos), while out of 266 carbamate products, only 76 were still available, with the active ingredient being carbaryl.[49]

The carbamate chlorfenapyr (marketed as Phantom) is a relatively new non-pyrethrin material, which some claim has an overall greater long term effectiveness than pyrethrins,[50] with bed bug resistance being only a recent development.[51] Chlorfenapyr is a non-repellent, slower but virulent long-lasting residual killer.[52]

Chlorfenapyr is part of a new class of chemicals called pyrroles, which are technically pro-insecticide, meaning the biological activity depends on its activation to another chemical, in the case of bed bugs leads to lethargy and death. However, due to its hazardous nature Phantom is not legal for sale to consumers in AK, CT, NY, MA, SC, and "is intended for use by individuals/ firms licensed or registered by the state to apply termiticide and general pest control products as a spot or crack and crevice spray."[53][54] And as it may require ten or more days to kill the bugs, during which the insect may still be active and females may wander and deposit viable eggs in other locations.

Another carbamate agent which appears to be most effective against bed begs, with long residual effect, is propoxur (marketed under the registered trademark name Baygon) a pesticide with a somewhat murky regulatory history. In a test of its effectiveness against bed bugs, while some of today’s leading pesticides could not kill even half of the bugs, propoxur as well as chlorpyrifos (an organophosphate) killed them all in an hour. However, Propoxur is a neurotoxin, toxic to humans if ingested, and EPA research has found human nervous systems could be harmed, with infants and children being in the most danger. Serious overexposure can also cause death by cardiorespiratory depression.[55] It is therefore, like chlorpyrifos,[56] banned by the EPA for use in locations where children may be present (residential buildings and hotels). Recently, the EPA denied a request by the state of Ohio to allow its use therein by licensed exterminators.[57]

Propoxur volatilizes in the air and can be absorbed into the blood weeks after application. It is also thought to be a cardiovascular or blood toxicant, a possible human carcinogen, a reproductive toxicant, and a neurotoxicant, due to its cholinesterase inhibiting properties, but it is not thought to be bioaccumulative.[58]

The third and most widely used class is that of pyrethrins and pyrethroids, which come from the chrysanthemum plant. This class includes synthetic pyrethroids such as allethrin, tetramethrin, permethrin, esfenvalerate, bifenthrin, cyfluthrin, cypermethrin, deltamethrin, d-phenothrin, imiprothrin, lambda-cyhalothrin, resmethrin, and tralomethrin, and which are contained in a variety of insecticides. This class is one of the least poisonous to mammals, and break down more rapidly (thus being more of a contact killer and having less residual effect) and works to control or kill insects by paralyzing their nervous system. However, these are considered less effective than many organophosphates and carbamates, and might be repellent to bedbugs. In addition bed bugs have now developed resistance to all pyrethroids labeled to control them. [59][60][61]

Currently, microencapsulated materials such as contain the pyrethroids esfenvalerate (Onslaught) or lambda-cyhalothrin (Demand CS) may offer the rapid reduction of susceptible populations.[62]

Also reported effective against some pyrethroid-resistant bugs were two pyrethroid-based dusts, (Tempo Dust;Drione) as well as diatomaceous earth.[63]

Botanical insecticides containing natural pyrethrins are also sometimes employed, and repel and can “knock down” bed bugs for a some time, but natural pyrethrins deteriorate quickly and fail to provide the necessary residual action which some other materials supply.

Isopropyl (rubbing) alcohol also works as a contact killer, as do most insecticides while others also provide some degree of residual effectiveness. Insecticides are classified according to their application method: Crease and Crevice, Indoor Surface, Indoor Space, and Fumigation. An additional factor is whether an insecticide repels bed bugs (causing migration if not killed), or not.

A supplementary type of insecticide is that of Insect Growth Regulators (IGR’s), such as hydroprene (Gentrol) and methoprene, which do not actually kill bed bugs, but instead are said to work to prevent reproduction by disrupting the development of immature bed bugs, resulting in bed bugs being unable to reproduce. This process takes longer but it can ensure an eventual end of the infestation, if contact with all bed bugs is made, but usually this chemical is used in conjunction with other insecticides.[64][65]

Extensive testing determine the relative safety of insecticides (especially for mammals)is required before chemical insecticides may be registered for use, but which may result in some potentially effective and relatively safe products (perhaps such as Bendiocarb) from never being marketed. Dini M. Miller, Ph.D., an associate professor in Urban Pest Management at Virginia Tech's Department of Entomology, explains that,

To get an EPA registration, the pesticide product has to be thoroughly tested for acute and chronic effects on mammals (laboratory rats and dogs), the potential effects on birds, fish, and honeybees has to be documented, and the environmental fate (half-life) of these products in water or soil also must be quantified. The cost of having a product registered is now estimated to be around $ 100 million. This cost naturally limits the number of products that make it to the marketplace. In addition, there has been a 10 to 15 year trend in reducing the number of pesticide products that receive registration for use in the indoor environment. In short, it is very hard to get new pesticides registered that are labeled for indoor use (as opposed to agricultural use). [66]

Natural insecticides

Natural insecticides include orange oil, cedar oil, freshwater food-grade Diatomaceous earth. The latter rightly applied, can slowly work to control or kill bed bugs by cutting them as they travel, often resulting in their death by dehydration. Silica aerogel (a synthetic desiccant dust) mixed with chemical insecticides has reported to be highly effective,[67] especially when combined with a blend of bed bug alarm pheromones.[68] Lower humidity is recommended for using diatomaceous earth, and the manner of application as well as the source of diatomaceous earth can be a deciding factor in how well it works, and more research is needed to establish its effectiveness.[69]

Pesticide resistance

Some studies have concluded that resistance to many of the chemical pesticides currently used is increasing in some bed bug populations in many areas of North America.[70][71] This Resistance is genetically conferred to subsequent populations which then show resistance to other chemical tools within the same class of chemistry. Thus the problem involves all pyrethroids and is likely only to get worse.[72] According to a report from the University of Kentucky College of Agriculture, some of the latest “super bed bugs” can survive for up to 16 days after being directly sprayed with currently used pesticides designed to kill insects immediately.

Bed bugs have a cuticle on the outside of their body that is almost impenetrable to many insecticides used today, therefore the bugs do not pick up the dried residues of such very well. Bed bugs developed resistance to DDT in the 1950s, and then to its successors such as organophosphates like diazinon and malathion which were being used to clear up remaining infestations.[73] DDT resistance can possibly lead to pyrethroid resistance, as both pesticide classes act on the same target site.[74] Entomologists at the University of Kentucky reported that some bed bug populations across the United States are resistant to pyrethroid insecticides, with some showing an 1,000-fold resistance to deltamethrin and lambda-cyhalothrin, compared to a susceptible laboratory strain. Researchers further found that seven of the eight field populations submitted by pest-management firms across the country were well over 100-fold resistant to deltamethrin.[75]

Before developing resistance, use of DDT dust, followed by malathion, diazinon, etc. (in addition to normal measures such as cleaning and laundering), was effective in largely eradicating bed bugs in the recent past, as a single thorough application of these older insecticides typically worked as bugs succumbed after crawling or resting contact with previously treated surfaces. As most of today's sprays lack similar residual potency (and with many also being repellent), desiccant (drying) dust formulations may play an increasing role in eliminating and preventing bed bugs in harborage areas.[76]

Repeat treatments with any insecticide are advised and are almost always necessary. Self-treatment is discouraged, and can make eradication much more difficult than when done by professional exterminators, trained in bed bug elimination. Spot treatment of bed bugs with chemical formulations can make matters worse by allowing them to disperse and or develop resistance to the insecticide used. Inhalation of all insecticides is to be avoided. Fogging is less advised, as besides the health risk to humans, they are considered to be less effective, and most contain pyrethroids, which has an associated excitatory flushing effect and by spraying into a space rather than harbourage, bugs are likely to disperse and can spread an infestation.[77]

Laundering

Certain items cannot be safely treated with insecticide, including cloths, and thus heat is prescribed. In one study, 30 minutes in the “hot” cycle of a dryer killed all life stages, while prolonged washing in 140°F water killed all life stages. Almost nothing died if soaked for two hours, and while all adults and nymphs died when soaked for 24 hours, yet all eggs survived.

Freezing

A study on freezing bed bugs showed that 2 hours at 1.4°F killed all bed bugs and eggs when placed directly (not in clothes) in the freezer. But when a bag of laundry was placed in the freezer, it took about 8 hours for the temperature at the center of the bag to reach 1.4°F.[78]

The supercooling point of bed bugs is -4°F, and one study showed that all bed bugs were killed by a direct 1 hour exposure to −3°F. However, bed bugs have the capacity for rapid cold hardening, so that a 1-h exposure to 32°F improved their subsequent tolerance of −7°F and −3°F respectively, requiring either longer duration or lower temperatures. [79]

Based upon research on other insects, it is stated that a minimum temperature of 23°F must be held for 5 days in order to kill bugs and eggs, while minus 15°F is said to instantly freeze the latter. Freezing also requires that bed bugs be actually in those temperature, versus simply the exterior of materials which house bed bugs being subjected to such.[80]

The EPA states that home freezers are usually not cold enough to kill bed bugs. Putting things outside in freezing temperatures can kill bed bugs, but it can take several days when the temperature is 0° F and almost a week when the temperature is 20° F.[81]

Volumetric heating

The most effective natural means of eliminating bed bugs involves pumping superheated air into an mildly pressurized (windows sealed) house, or heating individual room to around 140°F Temperature probes are used to ensure that internal temperatures are high enough to kill the bugs and their eggs.[82]

One study concluded that it is important to achieve and maintain temperatures of above 118.4°F (48°C) for more than 20 min to effectively kill all life stages of bed bugs, considering the clutter in treated spaces and the fact that bed bugs move to cooler temperatures, treatment times must be much longer to penetrate cracks and crevices, At 60-min exposure to 113°F , approximately 50% of adult bed bugs exposed survived, while 20% survived after 4 hours. Complete mortality was obtained at temperatures 118.4°F, 122°F, and 131°F for all exposure times except 10- min at 118.4°F. Even if some nymphs emerged, they did not develop at temperatures higher than 118.4°F. No differences in mortality were shown between fed and unfed bed bugs.

90% higher temperatures than previously reported were required to kill bed bugs when the temperature rose slowly — possibly because of the way previous heat tests have been conducted — but it is not known what enables bedbugs to resist gradual heat stress.[83]

Fumigation/gases

Use of controlled atmospheres (either single or gas mixtures) are an historical method used in the eradicating of bed bugs and other pests, typically offering superior effectiveness with less residual effects versus that of legal chemical pesticides, but which suffers from their own challenges and dangers.

Vikane/sulfuryl fluoride

Sulfuryl fluoride, gas, marketed under the name Vikane, is an option suited for use within contained entire structures, a procedure which takes one day and is reported to kills all bed bug adults, nymphs and eggs, if done properly. The manufacturer states that Vikane leaves no residue, rapidly dissipates, and that it does not cause significant damage to human health or environment, but it can dangerous to humans if breathed, and this use of Vikane is not legal everywhere.[84][85]

Sulfur dioxide

Sulfur, which when burned gives off sulfur dioxide gas, is the oldest known insecticide, when brimstone was used as a fumigant up to 3,000 years ago. It was used in the past against mildew and to sanitize houses quarantined due to infectious diseases such as smallpox and to kill household insects.[86] Anecdotal[87] and clinical reports testify of the past use of fumigation with sulfur dioxide (such as through the use of sulfur candles) showing that it was highly effective against bed bugs. In the late 1930 to the mid 1940s it was used in the United Kingdom to fumigate entire homes, and it is reported to have helped reduce infestations by up to 80% in one town under study.[88] One recommendation was the use of 20 fluid ounces of liquefied sulfur dioxide to 1200 cubic inches with a repeat treatment within two weeks.[89]

However, despite its historical use and effectiveness, it apparently is no longer legal to sell for consumer use in homes, although depending on location it may be used in greenhouses and possibly by professional exterminators in some cases, as it is dangerous to use due to the poisonous and suffocating vapors of the sulfur dioxide gas, while its chemical action on metals and coloring fabrics may leave undesirable effects.[90] Factors adversely affecting its effectiveness include the difficulty in penetrating all haborages, the higher resistance of eggs to the fumigant. Starvation and cold are factors which enhance the resistance of all bed bugs.[91] To be efficient it must burn rapidly, and some studies report it is not always successful. More clinical studies are needed in order to ascertain its effectiveness and the best manner of treatment. [92]

Carbon Dioxide

Experiments subjecting bed bugs to atmospheres of carbon dioxide resulted in 100 % mortality of all stages within 6 hours in an atmosphere of 100% C02, while a 60% volume produced the same effect within 24 hours. An atmosphere of 98% nitrogen resulted in only 10 - 20 % mortality after 72 hours.[93]

Chlorine dioxide

In clinical tests chlorine dioxide has been shown to be effective in killing bedbugs. [94]

Natural predators

Spiders are considered as primary natural predators of bed bugs. Several arthropod species such as cockroaches, ants, mites, etc. can attack and kill them. Rodents also can snack on the bed bugs. [95] An older report from 1902 describes the little red Pharaoh ant (MonoMorium Pharaonis) as being especially effective against bed bugs.[96]

Environmentalism

Environmentalists like to spread despair about bed bugs, hinting that evolution always makes them impervious to each new insecticide which people use to put down outbreaks. A typical examples is "They Crawl, They Bite, They Baffle Scientists" in the August 30, 2010 New York Times. The article lists half a dozen chemicals which don't kill bed bugs, while (carefully?) omitting any mention of effective chemicals.

The EPA will also soon be offering $550,000 in grants to state and tribal agencies for pilot projects relating to outreach and education. [97]

Additional research suggests that pyrethroid resistant bed bugs developed faster but produced fewer eggs than the susceptible strain bed bugs. Additional evaluations also indicate that field strain bed bugs may not survive the long periods of starvation previously suggested.[98]

Economic Impact

New York City's $30 billion tourism industry is threatened as travelers become skittish to travel where major infestations are occurring. [99]

American Folklore

Several variations of a children's rhyme exists whereby the bed bug is mentioned.

“

Sleep tight

don't let the bed bugs bite,
for if they do, take your shoe
and smack them in two

”

Author is unknown but the first known use of 'Sleep tight' can be found in a 1866 publication by American author Susan Bradford Eppes.